I would call that their story's progression, but the actual story's are not that similar.
Story Progression = Story
lineIf we are talking about pure story then it is not much different.
Let's compare Dragon Age: Origins to Mass Effect.
DA:O
-Starts off as a clueless person on his/her destiny
-Recruited into organization (Grey Wardens) to embark on adventure (defeat darkspawn)
-Form friendships/alliances (recruit armies and meet party members)
-Prepare for the big fight (Landsmeet, gathering of armies at Redcliffe)
-Big fight/climix (Retaking of Denerim, fighting Archdemon)
Mass Effect
-Starts off as clueless person on his/her destiny
-Recruited into organization (Spectres) and embark on adventure (defeat Saren which later evolves into Saren and Repears)
-Form friendships/alliances (meet party members, gather proof of Saren treachery to Council)
-Prepare for big fight (chase Saren and look for Prothean/Reaper information)
-Big Fight/climix (Assault on Citadel, full-blown revelation of Saren organic/machine hybrid and Sovereign)